Patent GB-572235-A (GB)
Title: Improvements in or relating to fluid control valves for double-acting hydraulic shock absorbers
IPC: F16F9/20
Filed: 1943-07-03
Abstract: 572,235. Hydraulic shock-absorbers. NEWTON, N. B. July 3, 1943, Nos. 10836/43 and 8978/44. [Class 108 (iii)] A fluid control valve assembly for a direct, double-acting, cylinder-and-piston, hydraulic shock-absorber comprises a closed transfer chamber in the piston and non-return valves therefor, each operating only as an inlet or as d an outlet valve, the valves controlling different a pairs of inlet and outlet ports for each direction k of flow through the chamber. Fig. 1 shows g part of a shock-absorber comprising a cylinder 10, piston 11, piston-rod 12 and piston-rod extension 13, the piston 11 being located on the rod by a collar 15 and ring 14, the collar carrying a light spring-pressed plate valve 16 covering outlet transfer passages 18. A tube 19, screwing at 20 on the piston-rod 12 and locked by a screw 21, secures the piston in position and at its other end the tube is attached by a part-spherical joint to the rod 13. Within the tube 19 a valve-seating 24 is threaded, having a tongue 25 engaging a slot in the end of the rod 13 so that relative rotation between the rod 13 and tube 19 will screw the seating 24 into or out of the rod for adjustment purposes. The end of the piston-rod 12 is formed with a passage 26 and lateral inlets 27 and the extreme inner end is formed as a valve seating 26a. Between the valve seatings 24, 26a is a valve assembly comprising a valve with a stem 28 and head 32 and, on the stem 28, a valve head 33 is slidably mounted and separated from the head 32 by a spring 34. A passage 35 and lateral inlets 36 in the rod 13 lead to the valve head 33 and outlet transfer passages 42 in an end plate 37 screwed on the tube 19 are covered by a spring-pressed plate valve 41. In operation, on movement of the piston to the right, fluid is forced through the lateral inlets 27 and passage 26 and pushes the valve 32 and its stem 28 away from the seating 26a, after which it flows through ports 44 in the tube 19 into the piston space 43 and then through the outlets 42 by lifting the valve 41. When the piston moves to the left, fluid is forced through the lateral inlets 36 and passage 35 and pushes the valve 33 along the stem 28, after which it flows through the ports 44, space 43 and outlet passages 18 by lifting the valve 16. Greater resistance is provided by the valve 33, which acts on the rebound stroke, than by the valve 32. In another construction, Fig. 2, movement of the piston b to the right forces fluid to flow through passages h therein and to open a spring-pressed valve-ring i<2>, after which the fluid flows through the centre of the valve-ring and through the centre of an adjacent valve-ring j<2> towards a valve q. The fluid pressure forces the valve q to slide towards the left together with a guide rod n against the action of a spring o, after which the fluid escapes through apertures m<3> to the other side of the piston. Movement of the piston b to the left forces fluid to flow through the apertures m<3> and lift the valve-ring j<2>, after which it opens the valve p and flows through the passages h to the other side of the piston. Compression of the spring o is adjustable by rotating the end of the piston-rod c so that the blade-like end d<1> of the extension rod d engages a nut r on the guide-rod n and screws it relatively thereto to move the rod n axially. Specifications 460,851 and 496,884 are referred to.